/*
** $Id: lmathlib.c,v 1.83 2013/03/07 18:21:32 roberto Exp $
** Standard mathematical library
** See Copyright Notice in lua.h
*/


#include <stdlib.h>
#include <math.h>

#define lmathlib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


#undef PI
#define PI	((lua_Number)(3.1415926535897932384626433832795))
#define RADIANS_PER_DEGREE	((lua_Number)(PI/180.0))



static int math_abs (lua_State *L) {
	lua_pushnumber(L, l_mathop(fabs)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_sin (lua_State *L) {
	lua_pushnumber(L, l_mathop(sin)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_sinh (lua_State *L) {
	lua_pushnumber(L, l_mathop(sinh)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_cos (lua_State *L) {
	lua_pushnumber(L, l_mathop(cos)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_cosh (lua_State *L) {
	lua_pushnumber(L, l_mathop(cosh)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_tan (lua_State *L) {
	lua_pushnumber(L, l_mathop(tan)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_tanh (lua_State *L) {
	lua_pushnumber(L, l_mathop(tanh)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_asin (lua_State *L) {
	lua_pushnumber(L, l_mathop(asin)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_acos (lua_State *L) {
	lua_pushnumber(L, l_mathop(acos)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_atan (lua_State *L) {
	lua_pushnumber(L, l_mathop(atan)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_atan2 (lua_State *L) {
	lua_pushnumber(L, l_mathop(atan2)(luaL_checknumber(L, 1),
		luaL_checknumber(L, 2)));
	return 1;
}

static int math_ceil (lua_State *L) {
	lua_pushnumber(L, l_mathop(ceil)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_floor (lua_State *L) {
	lua_pushnumber(L, l_mathop(floor)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_fmod (lua_State *L) {
	lua_pushnumber(L, l_mathop(fmod)(luaL_checknumber(L, 1),
		luaL_checknumber(L, 2)));
	return 1;
}

static int math_modf (lua_State *L) {
	lua_Number ip;
	lua_Number fp = l_mathop(modf)(luaL_checknumber(L, 1), &ip);
	lua_pushnumber(L, ip);
	lua_pushnumber(L, fp);
	return 2;
}

static int math_sqrt (lua_State *L) {
	lua_pushnumber(L, l_mathop(sqrt)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_pow (lua_State *L) {
	lua_Number x = luaL_checknumber(L, 1);
	lua_Number y = luaL_checknumber(L, 2);
	lua_pushnumber(L, l_mathop(pow)(x, y));
	return 1;
}

static int math_log (lua_State *L) {
	lua_Number x = luaL_checknumber(L, 1);
	lua_Number res;
	if (lua_isnoneornil(L, 2))
		res = l_mathop(log)(x);
	else {
		lua_Number base = luaL_checknumber(L, 2);
		if (base == (lua_Number)10.0) res = l_mathop(log10)(x);
		else res = l_mathop(log)(x)/l_mathop(log)(base);
	}
	lua_pushnumber(L, res);
	return 1;
}

#if defined(LUA_COMPAT_LOG10)
static int math_log10 (lua_State *L) {
	lua_pushnumber(L, l_mathop(log10)(luaL_checknumber(L, 1)));
	return 1;
}
#endif

static int math_exp (lua_State *L) {
	lua_pushnumber(L, l_mathop(exp)(luaL_checknumber(L, 1)));
	return 1;
}

static int math_deg (lua_State *L) {
	lua_pushnumber(L, luaL_checknumber(L, 1)/RADIANS_PER_DEGREE);
	return 1;
}

static int math_rad (lua_State *L) {
	lua_pushnumber(L, luaL_checknumber(L, 1)*RADIANS_PER_DEGREE);
	return 1;
}

static int math_frexp (lua_State *L) {
	int e;
	lua_pushnumber(L, l_mathop(frexp)(luaL_checknumber(L, 1), &e));
	lua_pushinteger(L, e);
	return 2;
}

static int math_ldexp (lua_State *L) {
	lua_Number x = luaL_checknumber(L, 1);
	int ep = luaL_checkint(L, 2);
	lua_pushnumber(L, l_mathop(ldexp)(x, ep));
	return 1;
}



static int math_min (lua_State *L) {
	int n = lua_gettop(L);  /* number of arguments */
	lua_Number dmin = luaL_checknumber(L, 1);
	int i;
	for (i=2; i<=n; i++) {
		lua_Number d = luaL_checknumber(L, i);
		if (d < dmin)
			dmin = d;
	}
	lua_pushnumber(L, dmin);
	return 1;
}


static int math_max (lua_State *L) {
	int n = lua_gettop(L);  /* number of arguments */
	lua_Number dmax = luaL_checknumber(L, 1);
	int i;
	for (i=2; i<=n; i++) {
		lua_Number d = luaL_checknumber(L, i);
		if (d > dmax)
			dmax = d;
	}
	lua_pushnumber(L, dmax);
	return 1;
}


static int math_random (lua_State *L) {
	/* the `%' avoids the (rare) case of r==1, and is needed also because on
	some systems (SunOS!) `rand()' may return a value larger than RAND_MAX */
	lua_Number r = (lua_Number)(rand()%RAND_MAX) / (lua_Number)RAND_MAX;
	switch (lua_gettop(L)) {  /* check number of arguments */
	case 0: {  /* no arguments */
		lua_pushnumber(L, r);  /* Number between 0 and 1 */
		break;
			}
	case 1: {  /* only upper limit */
		lua_Number u = luaL_checknumber(L, 1);
		luaL_argcheck(L, (lua_Number)1.0 <= u, 1, "interval is empty");
		lua_pushnumber(L, l_mathop(floor)(r*u) + (lua_Number)(1.0));  /* [1, u] */
		break;
			}
	case 2: {  /* lower and upper limits */
		lua_Number l = luaL_checknumber(L, 1);
		lua_Number u = luaL_checknumber(L, 2);
		luaL_argcheck(L, l <= u, 2, "interval is empty");
		lua_pushnumber(L, l_mathop(floor)(r*(u-l+1)) + l);  /* [l, u] */
		break;
			}
	default: return luaL_error(L, "wrong number of arguments");
	}
	return 1;
}


static int math_randomseed (lua_State *L) {
	srand(luaL_checkunsigned(L, 1));
	(void)rand(); /* discard first value to avoid undesirable correlations */
	return 0;
}


static const luaL_Reg mathlib[] = {
	{"abs",   math_abs},
	{"acos",  math_acos},
	{"asin",  math_asin},
	{"atan2", math_atan2},
	{"atan",  math_atan},
	{"ceil",  math_ceil},
	{"cosh",   math_cosh},
	{"cos",   math_cos},
	{"deg",   math_deg},
	{"exp",   math_exp},
	{"floor", math_floor},
	{"fmod",   math_fmod},
	{"frexp", math_frexp},
	{"ldexp", math_ldexp},
#if defined(LUA_COMPAT_LOG10)
	{"log10", math_log10},
#endif
	{"log",   math_log},
	{"max",   math_max},
	{"min",   math_min},
	{"modf",   math_modf},
	{"pow",   math_pow},
	{"rad",   math_rad},
	{"random",     math_random},
	{"randomseed", math_randomseed},
	{"sinh",   math_sinh},
	{"sin",   math_sin},
	{"sqrt",  math_sqrt},
	{"tanh",   math_tanh},
	{"tan",   math_tan},
	{NULL, NULL}
};


/*
** Open math library
*/
LUAMOD_API int luaopen_math (lua_State *L) {
	luaL_newlib(L, mathlib);
	lua_pushnumber(L, PI);
	lua_setfield(L, -2, "pi");
	lua_pushnumber(L, HUGE_VAL);
	lua_setfield(L, -2, "huge");
	return 1;
}

